42198209 has 2 divisors, whose sum is σ = 42198210. Its totient is φ = 42198208.

The previous prime is 42198181. The next prime is 42198227. The reversal of 42198209 is 90289124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 35438209 + 6760000 = 5953^2 + 2600^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42198209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (42194209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21099104 + 21099105.

It is an arithmetic number, because the mean of its divisors is an integer number (21099105).

Almost surely, 2^42198209 is an apocalyptic number.

It is an amenable number.

42198209 is a deficient number, since it is larger than the sum of its proper divisors (1).

42198209 is an equidigital number, since it uses as much as digits as its factorization.

42198209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 42198209 is about 6496.0148552786. The cubic root of 42198209 is about 348.1486158955.

The spelling of 42198209 in words is "forty-two million, one hundred ninety-eight thousand, two hundred nine".